Characterization of two non-testis-specific CABYR variants that bind to GSK3beta with a proline-rich extensin-like domain

Biochem Biophys Res Commun. 2005 Apr 15;329(3):1108-17. doi: 10.1016/j.bbrc.2005.02.089.


To explore more possible roles for GSK3beta function, the yeast two-hybrid screening using GSK3beta as a bait protein was performed. In this study, we demonstrated that two variants of CABYR (281 and 379) interacted with GSK3beta in the yeast two-hybrid and GST pull down assay. Molecular characterization showed that CABYR variants formed a dimer with a proline-rich extensin-like domain, which slightly overlapped with GSK3beta-binding site. In kinase assay, we also showed that CABYR variants act as an ideal substrate for GSK3beta within the extensin-like domain and phosphorylation sites on CABYR were mapped. Interestingly, Northern blot showed that CABYR transcripts were expressed more distinctly in the fetal brain than in the adult brain, suggesting that this protein may play a role during brain development. Moreover, differential expression of CABYR variants may exhibit aberrant expression in brain tumors and cancer cell lines.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Binding Sites
  • Brain / metabolism*
  • Brain Neoplasms / metabolism*
  • Calcium-Binding Proteins / genetics
  • Calcium-Binding Proteins / metabolism*
  • Cells, Cultured
  • Glycogen Synthase Kinase 3 / genetics
  • Glycogen Synthase Kinase 3 / metabolism*
  • Glycogen Synthase Kinase 3 beta
  • Glycoproteins / metabolism
  • HeLa Cells
  • Humans
  • Male
  • Molecular Sequence Data
  • Organ Specificity
  • Phosphoproteins / genetics
  • Phosphoproteins / metabolism*
  • Plant Proteins / metabolism
  • Proline / metabolism*
  • Protein Binding
  • Protein Isoforms / genetics
  • Protein Isoforms / metabolism
  • Protein Structure, Tertiary
  • Sequence Homology, Amino Acid
  • Structure-Activity Relationship
  • Testis / metabolism
  • Tissue Distribution


  • CABYR protein, human
  • Calcium-Binding Proteins
  • Glycoproteins
  • Phosphoproteins
  • Plant Proteins
  • Protein Isoforms
  • extensin protein, plant
  • Proline
  • GSK3B protein, human
  • Glycogen Synthase Kinase 3 beta
  • Glycogen Synthase Kinase 3